Bairdia letangae Forel, 2011

Forel, Marie-Béatrice & Crasquin, Sylvie, 2011, In the aftermath of Permian-Triassic boundary mass-extinction: new ostracod (Crustacea) genus and species from South Tibet, Geodiversitas 33 (2), pp. 247-263 : 253

Bairdia letangae Forel n. sp. ( Fig. 3 A-E)

TYPE MATERIAL. — Holotype: one complete carapace (P6M2596; Fig. 3A ); paratype: one complete carapace (P6M2595; Fig. 3B ).

ETYMOLOGY. — Dedicated to Béatrice Letang, personal dedication.

MATERIAL EXAMINED. — 7 complete carapaces and 2 single valves.

DIMENSIONS. — L = 540-785 µm; H = 320-500 µm. Holotype: L = 785 µm; H = 492 µm. Paratype: L = 540 µm; H = 320 µm.

TYPE HORIZON. — Sample 06Ti30, unit VI, Tulong Formation, Early Anisian, Middle Triassic.

TYPE LOCALITY. — Tulong section, Southern Tibet .

OCCURRENCE. — Tulong section, Southern Tibet . Samples 06Ti21, 06Ti30, 06Ti31 and 06Ti34, Tulong Formation, units V and VI, Spathian-Anisian, Early-Middle Triassic.

DIAGNOSIS. A massive species of ornamented Bairdia with AB and PB flattened, large reticulation on all the carapace except the dorsal margin.

DESCRIPTION

At RV, PDB straight, DB long and more or less horizontal, ADB straight to gently concave. At LV all dorsal parts form a regular arch. AB with quite small radius of curvature; AVB and PDB regularly arched; VB straight at LV, gently concave RV; PB with medium radius of curvature; maximum of curvature of PB and AB located at the same H; carapace strongly compressed along free margins and particularly in AB and PB; surface ornamented by a large reticula-

tion, this reticulation is present on all the surface except for dorsal margins of both valves.

REMARKS

Bairdia letangae Forel n. sp. is similar to Bairdia ortiseiensis Crasquin, 2008 from the Late Permian of the Tesero section (Northern Italy; Crasquin et al. 2008). Here the DB is longer, the radius of curvature of AB is more important and the overlap is stronger. Compared to Lobobairdia zapfei Kozur, 1971 from the Anisian of Balaton area ( Kozur 1971; Monostori 1995), Bairdia letangae Forel n. sp. has a straighter DB and reticulation present all over the carapace surface.

Figures

FIG. 3. — Specimens from Tulong section (Tibet), stored at the Pierre et Marie Curie University Collections (Paris,France):A-E, Bairdia letangae Forel n. sp.; A, holotype (P6M2595), right lateral view of a complete carapace; B, paratype (P6M2596), right lateral view; C, right lateral view of a broken carapace (P6M2597); D, right lateral view of a broken carapace (P6M2598); E, left lateral view of a